Vibrator circuit



April 6, 19 48. M. SLATER VIBRATOR CIRCUIT Filed Sept. 1, 1944 INVEN TOR. fra 15. J/a/er Patented Apr. 6, 1948 UNITED STATES PATENT OFFICE mifil'ii'fma Ira M. Slater, Indianapolis, Ind asalgnor to P. R.

Mallory & 00., Inc., Indianapolis, Ind., a corporation of Delaware Application September 1, 1944, Serial No. 552,228

Claims. (Cl. 175-373) 2 brators and regardless of contact wear. changes in contact adjustment, and other variables. I

It is also within the contemplation of the invention to providea vibrator circuit, including As those skilled in the art know, conventional 5 a pair of vibrators tuned to the same operating vibrators essentially comprise a vibratory reed frequency, .in-which each vibrator during the adapted to control a system of contacts and an operation thereof transmits a controlling or synelectromagnetic driver system whereby the reed chronizing signal to the other, whereby theconmay be maintained in vibration to interrupt the dition' of exact synchronism is positively malnflow of current in the primary winding of a trans- 1 tained under the most rigorous operative condiformer at a rapid rate. The amount of current tions. which may be controlled by a, vibrator is limited The invention also contemplates a vibrator sysby the current-carrying ability of the system of tem constituted of two vibrators mutually incontacts as excessive currents cause strong confluencing their operating frequency towards extact sparking and greatly reduce the useful life act synchronism which is simple in character, of the vibrator. In general, it is not considered positive and foolproof in operation and which advisable to handle currents over five amperes may be readily manufactured and sold on a pracby means of a single vibrator, and when currents tical and commercial scale at a low cost. in excess of five amperes are to be interrupted, other d f ther objects and advantages of parallel connection of vibrators is resorted to. 2 the invention will become app nt from the fol- Various systems have been worked out to oplowing description, taken in conjunction with the crate two, or more, vibrators in parallel, but pracaccompanying drawing, illustrating a typical cirtical dimculties were frequently encountered in cuit organization embodying the invention. the applications of such systems. Parallel opera- While a preferred embodiment of the invention of a plurality of vibrators is predicated upon tion is described herein, it is contemplated that maintaining perfectly synchronous operation of considerable variation may be made in the meththe several vibratory reeds, this condition being od of procedure and the construction of parts obtained in most cases by initially tuning the without departing from the spirit of the invenreeds to the same natural irequencyand by contion. In the following description, and in the nectlng their driver coils together so that they claims, parts will be identified by specific names, are substantially synchronously energized. While for convenience, but they are intended to be these operating conditions could be obtained by as generic in their, application to similar parts 7 a sumcient amount of part selection during the as the art will permit.

manufacturing process, experience has shown Referring now more articularly to the drawthat the synchronous conditions thus obtained ing, the preferred organization of the inventionare maintained with dimculty for extended opincludes two vibratory interrupters generally deerative periods as the wear upon the contacts of noted by A and B. Vibrator A comprises a vithe several vibrators, the distribution of load bratory reed it clamped at one end thereof, and therebetween, etc., would change their operating carrying a pair of vibratory interrupter contacts frequencies. Although from time to time vari- 12 and it at an intermediate portion thereof. ous suggestions and proposals were made to elim- Vibratory contacts i2 and i3 cooperate with relmate the foregoing difliculties and to provide a atively fixed contacts it and i5, respectively. completely reliable synchronous vibrator system, The armature is under the control of two coils none, as far as is known, of these suggestions placed around the same iron core, of which coil and proposals was completely satisfactory and I5 is the driver coil, while coil ii is a synchrosuccessful when carried into practice on a pracnizing or control coil. In general, the driver coil tical and commercial scale. is constituted of many turns of wire, while the It is an object of the present invention to prosynchronizing or control coil is constituted of a vide a completely satisfactory solution of the outfew turns of wire so that its magnetic effect is standing problem. merely a small fraction of that of the main driver It is another. object of the present invention coil, such as, for example, 10%. Thetwo coils to provide a vibrator system in which two viare connected to produce magnetic fields of opbrators initially tuned to substantially identical posite direction, for reasons which will appear frequencies may be maintained in synchronous more fully as the description proceeds. Reed l0 operation throughout the useful life of the viis connected to terminal l8 of the vibrator and to ground, stationary contacts I4 and I5 are connected to terminals I9 and 20, respectively. One end of coils I8 and I1 is connected together and to reed I0, the other end of coil I6 is connected to stationary contact I 4, while the other end of coil I I is connected to terminal 2 I.

Vibrator B is the exact duplicate of vibrator A and is tuned to substantially the same operating frequency. Its elements are denoted by simi-- lar reference characters III to 2| in exact correspondence with elements III to 2| of vibrator A so that it will not be necessary to repeat description of the vibrator organization.

The two vibrators are electrically associated with the same step-up transformer 22, having two primary windings 23 and 24 and a common secondary winding 25, and are energized from the same source 26 of low direct current voltage, one terminal of which is connected to the center tap of both primary windings and the other terminal of which is grounded. The two fixed contacts of vibrator A, It and I5, are connected to the two ends of primary winding 23 through vibrator terminals I9 and 20, respectively, whereas the fixed contacts of vibrator B, It, I5, are connected to the two ends of primary winding 24 through vibrator terminals I9 and 26', respectively. In addition,'terminal 2| of vibrator A is connected to terminal I9 of vibrator B and terminal 2I' of vibrator B is connected to terminal I 9 of vibrator A.

From the foregoing description, the operation of the vibrator system of the invention will be readily understood by those skilled in the art. Considering first vibrator A and disregarding the operation of synchronizing or control coil II, it will be noted that driver coil I6 will be energized. its circuit being from the positive terminal of source 26, the upper half of primary Winding 23, driver coil I6, terminal I8, and through ground back' to the negative terminal of the source. Reed III will be deflected, until vibratory contact I2 closes with fixed contact I4, and short-circuits the driver coil. Upon the driver coil being deenergized, reed I II will be returned by its compliance beyond its original position to bring contacts I3 and I5 into engagement and then swings back into its center position where the deflecting force of the driver coil becomes again eiTective and a new cycle of operation is initiated. Thus, the reed will be maintained in continuous vibration and will alternately ground the two ends of primary winding 23 through fixed contacts I 4 and I5, alternately passing current in opposite directions through the two halves of the said primary winding-in a manner well understood.

The same remarks apply to vibrator B which will be operated in exactly the same manner and will alternately pass current in opposite directions through the two halves of primary winding 24. As is indicated by the arrows on transformer 22, the two primaries are so wound and connected in circuit that their fluxes are additive in the portion of the core within secondary winding so that an alternating current voltage corresponding to the vectorial sum of both primary currents will be induced in the said secondary winding. This alternating voltage may be rectified by means of a pair of half-wave rectifier tubes 21 and 28, the plates of which are respectively connected to the two ends of the secondary winding. The direct current output may be taken off between terminals 29 of which one is connected to the cathodes of both rectifier tubes, while the other is connected to the center tap of the secondary winding, 01. course, this manner of operation is only true in case the two vibrators are operating inexact synchronism as a result of their initial tuning to the same frequencies; It is, of course, possible to eliminate the rectifiers where A. 0. output is desired.

To understand the function and the operation I of control or synchronizing coils I1 and I1, let

us first assume that the two vibrators are operating in exact synchronism. Control coil I! being connected across driver coil I6, it will be energized synchronously and in phase with the said coil. The same applies to control coil I1 of the other vibrator which is energized from and in phase with the current in driver coil I6. As the fields of control coils I1 and II are oppositely directed to those of the respective driver coils on the same core, they will have no effect upon the synchronism of the two vibrators except that they will slightly weaken the magnetic field of each and will slightly reduce their amplitudes by equal amounts. This condition will be maintained as long as the two vibrator reeds are moving in exact synchronism. It will be understood that the term synchronism, as used in the specification and the appended claims, refers to operation of the two interrupters at the same frequency and in the same phase relationship.

In case for any reason vibrator A will operate at a frequency in excess of that ofvibrator B, reed II] will lead reed III, and contact I4 will be closed before contact It. In other words, driver coil I6 will be tie-energized before driver coil I6. Therefore, control coil ll of vibratory A, energized in phase with drivercoil I6 of vibrator B, will remain energized for a short interval even after driver coil I6 has been already de-energlzed. Since the field of control I1 is oppositely directed to that of driver coil IE, it will cause a more rapid collapse of the fiux in the core, to more rapidly reduce the pull of the electromagnet on armature I l of reed I0, thereby slowing down theoperation of vibrator A.

In case vibrator A operates at a frequency below that of vibrator B, contact I4 will close before contact I4, and thus control coil II will be de-energized before driver coil I6. As the fields of coils I6 and I! are oppositely directed, the absence of the field of coil I! will increase the field of driver coil I6 so that the reed III will be subjected to a stronger deflecting force and will be speeded up. Of course, the frequency control between the two vibrators is mutual, because whenever one of the vibrators is operating slower than the other, the other is operating faster than the first, and vice versa, so that the frequency of both vibrators will be influenced in such direction as to eliminate any frequency difference and to stabilize the frequency of operation somewhere between the two frequencies the vibrators would have in the absence of any stabilizing means.

Asthe control coils should have a much weaker magnetic field than the driver coils, they should be designed to have higher resistance or be connected in series with external regulating resistances.

The advantages of the circuit of the invention are numerous.- First of all, synchronous operation is obtained within a few cycles after the operation of the vibrators has been initiated and such synchronism is automatically maintained substantially throughout the useful life of the vibrators, regardless of normal contact wear, and other variables. Also, while the two vibrators are I interrelated for mutual frequency control, their load circuits are substantially independent so that upon failure of eitherone of the vibrators, the

other, vibrator will remain in operation and may.

provide emergency service until the defective vibrator is replaced. This feature is of very great practical importance in certain applications such as when Operating police radios, army transmitters and receivers, etc., where service has to be maintained under all conditions. Moreover, the circuit of the invention is extremely simple and provides a simple and eflicient way of taking care of power supply requirements in excess of. the normal power-handling ability of a single vibrator, The twin vibra'tor system of the invention also may be advantageously employed in cases where the current requirements could be handled by a single vibrator. By splitting up the load between two vibrators, a useful life many times longer than that of a single vibrator may be realdriver coil, and a synchronizing coil, 8. driver cir-.

cuit for said interrupters including a source of current and said driver coils thereby to effect vibratory motion of said reeds, and a synchronizer circuit including leads connecting the synchro-. nizing coil of each interrupter in parallel with the driver coil of the other thereby maintaining said reeds in exact synchronism. 2.. A vibrator system comprising, in combination, a pair of vibratory interrupters having substantially the same operating frequencies; each of said interrupters including a. vibratory reed, a system of contacts actuated by said reed, a driver coil, and a synchronizing coil having substantially fewer turns than said driver coil; a driver on? cuit for said interrupters including a source of current, said system of contacts, and said driver coils thereby to effect vibratory motion of said reeds; and a synchronizer circuit including leads connecting the synchronizing coil of each interrupter in parallel with the driver coil of the other thereby maintaining said reeds in exact synchronism.

3. A vibrator system comprising, in combination, a pair of vibratory interrupters having substantially identical operating frequencies; each of said interrupters including a vibratory reed, a paramagnetic core member, a. driver coil and a synchronizing coil mounted on said corememher; a driver circuit for each interrupter including the driver coil thereof and a current source, each energization of said driver coil producing a field in said core member of proper polarity to maintain vibration of the associatedfreed; and means for electrically coupling the synchronizing coil of each interrupter with the driver coil of the other so that each energization of the synchronizing coil produces a field in the associated core member of opposite polarity from the driver coil fieldkwhereby fields of unequal intensity are pro-' duced in the respective core members when the interrupters are out of synchronism, said unequal fields shifting the operating frequencies of the interrupters in opposite directions converging towards a common mean frequency.

4. A vibrator system comprising, in combination, a pair of vibratory interrupters having substantially identical operating frequencies; each of said interrupters including a vibratory reed, a paramagnetic core member, a driver coil and a synchronizing coil mounted on said core member; a driver circuit for each interrupter including the driver coil thereof and a current source, each energization of said driver coil producing a field in said core member of proper polarity'to maintain vibration of the associated reed; and a synchronizer circuit including leads connecting the synchronizing coil of each interrupter in parallel with the driver coil of the other so that each energization of the synchronizing coil produces a field in the associated core member of opposite polarity from the driver coil field whereby fields of unequal intensity are produced in the respective core members when the interrupters are out of synchronism, said unequal fields shifting the operating frequencies of the interrupters in opposite directions converging towards a common mean frequency.

5. A vibrator system comprising, in combination, a pair of vibratory interrupters having substantially identical operating frequencies each of said interrupters including a vibratory reed, a system of contacts operable thereby, a paramagnetic core member, a driver coil and a synchronizing coil mounted on said core member, said synchronizing coil having substantially fewer turns than said driver coil; a driver circuit for. each interrupter including the driver coil thereof, said system of contacts, and a current source, each energization of said driver coil producing a field in said core member of proper polarity to maintain vibration of the associated reed; and

opposite polarity from" the driver coil field whereby fields of unequal intensity are produced in the respective core members when the interrupters are out of synchronism, said unequal fields shifting the operating frequencies of the interrupters in opposite directions converging toi wards a common mean frequency. IRA M. SLATER.

nnranancas crrim The following references are of record in the file of this patent:

UNITED STATES ra'rnn'rs Great Britain' Dec. 16, 1938 

